Field of the Invention
The present invention relates to a torque limiter for a power winch, and more particularly to the torque limiter applied to a power winch and capable of timely cutting off the power whenever the reverse torque produced by a carrying load exceeds the bearable torque of the power supply, so as to prevent the power winch from being damaged by overload.
Description of the Related Art
Power winch is a device designed for hanging or dragging a load. For example, a hoist is a common application of the power winch, and a cable winch installed at the front of a jeep or a cross-country vehicle for trailing another car (to help others) or moving out of danger (to rescue oneself) is another common application of the power winch. The principle of operating the power winch is to output a forward or reverse transmission power by a power supply (such as a power motor) and acted by a reduction mechanism to drive a cable wheel to rotate in a forward or reverse direction to release or retrieve a cable, and a load (such as a heavy object, another car, or another object) is hooked by a heavy-duty hook installed at a front end of the cable, so as to move the load conveniently.
Since the winch carries a load (such as goods, objects, or people waiting to be rescued), and the load sometimes exceeds the torque bearable by the power supply (which involves the loading capacity of the power supply), therefore a torque limit mechanism for preventing any torque produced by the load and unbearable by the power supply is generally installed in a transmission mechanism, such that if an overload occurs, the torque limit mechanism will rotate idly and slip and will no longer transmit power, so as to protect the transmission mechanism (such as a power motor, a reduction mechanism, etc) of the power winch, and prevent the components of the power winch from being damaged by the overload. However, the conventional power winch generally uses a conventional circuit breaker as the torque limit mechanism, such that when the torque of the load increases, the current of the power supply current also increases. Therefore, the power of the power supply will be disconnected when there is an overload of current, so as to provide the effect of limiting the torque indirectly. However, the circuit breaker cannot be turned off or on immediately when the circuit breaker is used as a torque limit mechanism, due to the time lapse. Therefore, the power of the power winch cannot be stopped immediately when there is an overload, but the output of power will continue for a short period of time before the power winch stops. Obviously, such application causes tremendous trouble to users and requires further improvements.